Larger elm leaf beetle

Monocesta coryli (Say) (Coleoptera: Chrysomelidae)

Orientation to pest

The larger elm leaf beetle, Monocesta coryli (Say), is a native insect in the United States that is of concern in Florida as an occasional pest of elms (Umus). It has a similar biology to the invasive elm leaf beetle, Xanthogaleruca luteola (Müller), but is not as damaging, in part because it has only one generation per year. Young larvae feed in groups on elm leaves but older larvae disperse and feed singly. Larval feeding causes leaves to become skeletonized, giving trees a brown or defoliated look. Mature larvae leave trees to pupate in the soil.

Hosts commonly attacked

The larger elm leaf beetle feeds on various elms (Ulmus).

Distribution

This beetle occurs spottily from Florida to Pennsylvania, and west to Ohio and Kansas.

Images of larger elm leaf beetle

Clemson University - USDA Cooperative Extension Slide Series, Bugwood.org 768x512 / 1536x1024 Clemson University - USDA Cooperative Extension Slide Series, Bugwood.org 768x512 / 1536x1024	North Carolina Forest Service Archive, Bugwood.org 768x512 / 1536x1024
Figure 1. Views of the adult larger elm beetle, Monocesta coryli	Figure 2. Female of larger elm leaf beetle with egg mass

Gerald J. Lenhard, Louiana State Univ, Bugwood.org 768x512 / 1536x1024 Gerald J. Lenhard, Louiana State Univ, Bugwood.org 768x512 / 1536x1024	Jim Baker, North Carolina State University, Bugwood.org 768x512 / 1536x1024 Jim Baker, North Carolina State University, Bugwood.org 768x512 / 1536x1024
Figure 3. Young larvae of larger elm leaf beetle (left) feed in groups; close up of one larva (right)	Figure 4. Defoliated elms fed on by larger elm leaf beetle

Important biological control agents related to this pest species

No natural enemies of this species have been well documented, but the tachinid Icelia triquetra (Olivier) is reported to attack this species.

Web links for information on larger elm leaf beetle

• Featured Creature Fact Sheet, University of Florida and FDACS

Articles

• Anderson, D. and C. S. Papp. 1961. The larger elm leaf beetle, Monocesta coryli (Say). Proceedings of the Entomological Society of Washington 63: 203-207.
• Kelsheimer, E. G. 1945. Notes on the great elm leaf beetle. Florida Entomologist 28: 25-27.
• Kelsheimer, E. G. 1957. Larger elm leaf beetle (Monocesta coryli). Cooperative Economic Insect Report, Plant Pest Control Division, Agricultural Research Service, U.S. Department of Agriculture 7: 650.
• Madden, A. H. 1940. Larger elm leaf beetle (Monocesta coryli Say). Insect Pest Survey Bulletin, Bureau of Entomology and Plant Quarantine, U.S. Department of Agriculture 20: 408.